<!-- 过长提示 -->

<template>
  <div><u-form ref="form">
    <u-form-item label="用户名">
        <u-input maxlength="4" maxlength-message="不超过4个字符" placeholder="不超过4个字符"></u-input>
    </u-form-item>
</u-form></div>
</template>